Abstract:
Geochemical studies on the tritium chronology of Lake Vanda, the natural abundance of nitrogen isotopes in soil and evaporites in the Dry Valleys and observations of the sequential changes in the saline lakes, especially Don Juan Pond, were planned to search for the salt origin and to elucidate the geological history of the area. Glacial ice, subsurface ice, subsurface layered salt deposits, ... algae, fossil and lake water samples were collected mainly in the Wright Valley to investigate the geological history of the area. At Lake Vanda and the adjacent area, vertical distribution of water temperature, dissolved oxygen, pH, alkalinity and electrical conductivity in the lake was observed and sampling of lake water for the analysis of trace elements such as mercury was conducted at the deepest point of the lake. The evaporates, soil and algae for studying nitrogen isotope ratio were collected mainly around the lake and on the way to Bull Pass. Lake ice and subsurface lake water were collected at the east lobe of Lake Vanda for studying tritium chronology. A geochemical survey was completed of Don Juan Pond to see the change of the pond size in a short period. Shallow drilling was completed in conjunction with another science event and dry sediments were collected from this method for analysis. One saline pond and three freshwater pond water samples were collected from the Labyrinth area of the Wright Valley and analysed for chemical composition of the ponds. Salt spring location was investigated in the Taylor Glacier.

Quality
The Japanese geochemical studies in the McMurdo Dry Valleys region started in the 1963/64 field seasons when the geochemists were invited to conduct investigations in the area. Investigations continued in the area until the 1986/87 field season. The New Zealand Antarctic program supported work from the 1970/71 seasons to the 1986/87 season. The extensive studies provide ... geochemical data including general characteritics, major and trace elements, nutrients, organic matter, stable and radioisotope data and secondary minerals of lakes, ponds and their surroundings. The data is summarised in a single publications:

Matsumoto, G. Torii, T. Hanya, T. Distribution of organic constituents in lake waters and sediments of the McMurdo Sound region in the Antarctic. Memoirs of the National Institute of Polar Research 12(special issue): 103-120, 1979.